RE:solid STL, STEP, CAD Viewer

RE:solid 3D viewer opens engineering 3D models on Android. It reads mesh and CAD formats, computes geometry on device and saves your work to a file. No cloud, no sign-up, no internet.

📁 FORMATS
• STL — binary and ASCII; edge smoothing: strong, medium or off
• OBJ — with MTL, i.e. materials and colours
• 3MF — part names and colours, including per-face
• PLY — vertex colours, the 3D scanner format
• STEP / STP, IGES / IGS, BREP — CAD solids [PRO]
• ZIP — archive contents listed: open one model, or all as one assembly
• RE:solid project — the model with the state of your work

🔄 CAD CONVERSION [PRO]
STEP, IGES and BREP are read by the built-in OpenCascade kernel, locally: the file is never uploaded. An assembly arrives as a tree of named parts, not one solid piece. Saving to STL, OBJ or 3MF makes it a STEP → STL converter on the phone. Your first CAD file opens straight away, spending a trial session.

📏 MEASUREMENTS [PRO]
• Distance between points with vertex snapping, along the normal, per axis (ΔX, ΔY, ΔZ)
• Angle between faces, radius, diameter and centre of a circle from three points
• Wall thickness with one tap on the surface
• Measurement history, copy to clipboard; millimetres or inches

🌡 THICKNESS MAP [PRO]
The whole part at once: red is thin, blue is thick. Two scales: a gradient, and a threshold that reddens anything below your number. The thinnest wall is given as a number and a callout on the model, visible through it. In an assembly each part is measured on its own. The map is stored in the project.

✂️ SECTION [PRO]
A cutting plane along X, Y, Z or the view. The cut is capped and the plane stays visible; an open mesh gets no cap, and the app says so.

⚖️ WEIGHT AND COST [PRO]
Volume, area and mass for 10 materials: PLA, PETG, ABS, PA12-CF, gold 14K/18K, silver 925, steel, copper, aluminium. Each material keeps its own price per gram. Hidden parts are excluded, so you can weigh a sub-assembly. On an open mesh the result is marked approximate.

🔩 EXPLODE AND ANIMATION [PRO]
• Automatic explode in assembly order: what is covered comes off later
• Manual tuning: arrows set a part's direction and travel, a group's number its place in the order
• Move, rotate and scale a part — same handle, or type the numbers
• Video (MP4 or WebM) with a set number of passes and turns, looping seamlessly
• PNG frame capture, without the app interface

📦 PROJECT [PRO]
The model and your work in one file: orientation, part colours, hidden parts, the section, the manual explode with its order, the thickness map, camera. A note and attachments (photos, PDFs) live there too. The original model is inside, so a project opens on another device without the source file. Prepared geometry comes too: a heavy STEP assembly opens in a fraction of a second.

🗂 FILES
Models live in a folder in the app: subfolders, snapshots, search, format filter. Recent files. Opens from a file manager, messenger, mail or cloud.

👁 VIEWING
Shaded and Rendered modes with materials (gold, silver, chrome, copper, glass, diamond), technical modes — wireframe, X-ray, ghosted [PRO], the parts list with file names, dimensions, splitting an STL into solids. The palette colours the whole model, even parts coloured in the file; ↺ restores them.

⭐ RE:SOLID PRO
Free: viewing STL, OBJ, 3MF, PLY and ZIP, the library, view modes, materials, whole-model colour, part selection, the parts list, dimensions, STL splitting, smoothing.

One-time purchase (no subscription) unlocks: STEP, IGES and BREP conversion; projects with notes; explode, move and scale of a part; animation and frame capture; section; measurements and the thickness map; weight and cost; technical modes; part colour and material; hiding and isolating parts; saving to STL, OBJ, 3MF.

Three trial sessions: each unlocks every Pro tool until you close the app.

Everything is computed on the device, models are never uploaded.

Recent changes:
Custom colour
• A rainbow circle in the palette: a hue square and a HEX field for the exact colour of your filament.
• History: your last six custom colours at hand.
• Works for the whole model and for a single part.
• Your colour is saved in the project.
• The thickness map now catches thin part ends it used to miss.
• Edge smoothing now switches on models opened from a project too.
• Minor fixes.